Strengthening of brick infilled RC frames with different aspect ratios by means of CFRP overlays

Abstract

Post earthquake field investigations reveal that frames with inferior detailing are vulnerable to seismic actions. The presence of a large building stock in Turkey, which is vulnerable to an imminent earthquake, entails fast, relatively easy, and feasible alternative strengthening methods. In this paper, the strengthening of brick infilled walls with fiber reinforced polymer (FRP) overlays, and integrating them to the load carrying system of the frame, is considered as an alternative method for building upgrading. The effectiveness of the FRP overlays on frames with different aspect ratios, is an issue to be investigated. For this purpose, three reinforced concrete (RC) frame specimens with one-third scale and infilled with hollow clay tile (HCT) were strengthened with FRP overlays. The frame specimens had a single bay and two stories, and were tested to failure. The strengthening scheme was shifted, depending on the aspect ratio of the specimens. Test results were evaluated in terms of base shear-roof drift hysteretic response, and a macro model using the well-known equivalent diagonal strut concept was proposed to predict the lateral capacity and the response of the strengthened frames. The model predicted secant stiffness and failure load in an acceptable accuracy range. Theoretical and experimental results proved that aspect ratio significantly affects the level of strengthening attained. The study presented here is part of a comprehensive research work on the strengthening of HCT infilled RC frames, with different aspect ratios by means of various carbon fiber reinforced polymer (CFRP) schemes.

Keywords

• aspect ratio
• brick masonry infilled frames
• cfrp
• equivalent diagonal strut
• hysteretic response
• reinforced concrete
• strengthening